Alkenylsuccinic anhydride composition and method of using the same

ABSTRACT

The invention relates to an aqueous sizing composition comprising (a) an emulsion comprising an alkenylsuccinic anhydride component containing alkenylsuccinic anhydride particles suspended in a first starch component containing emulsifying starch selected from the group consisting of non-ionic starches, ionic starches, and mixtures thereof, and (b) a second starch component selected from the group consisting of non-ionic starches, ionic starches and mixtures thereof, such that the alkenylsuccinic anhydride and the starch in the emulsion and the second starch component are present at a starch: alkenylsuccinic anhydride weight ratio that is sufficiently high to enable the sizing composition to impart useful sizing properties to a fibrous substrate when the sizing composition contacts the fibrous substrate. The invention also relates to fibrous substrates treated with the sizing composition, processes for making the composition and processes for using such a composition, and other compositions. In one embodiment, alkylene ketene dimer is used instead of alkenylsuccinic anhydride.

BACKGROUND

Papermakers would benefit from a simple, effective, starch-based,cellulose-reactive surface-applied sizing agent system that (i) impartsuseful sizing properties to fibrous substrates and (ii) reduces oreliminates the need to use sizing agents at the wet end of a papermakingprocess. Unfortunately, known methods and compositions have preventedpapermakers from achieving this goal.

It is well known that the property of sizing, as applied to paper,refers to a fibrous substrate's ability to resist wetting or penetrationof a liquid into a paper sheet. Aqueous dispersions of alkenylsuccinicanhydride (ASA) cellulose-reactive sizing agent have been widely used inthe paper and board making industry for many years, for sizing a widevariety of grades which include printing and writing grades and bleachedand unbleached board grades. Cellulose-reactive alkenylsuccinicanhydride emulsions impart hydrophobic properties to the paper and boardproducts.

Chemicals used to achieve sizing properties are known as either internalsizes or surface sizes. Internal sizes can be either rosin-based orsynthetic sizes such as alkenylsuccinic anhydride, or other materials.Internal sizes are added to the paper pulp prior to sheet formation.Surface sizes are sizing agents that are added after the paper sheet hasformed, most generally at the size press, although spraying applicationsmay also be used.

Alkenylsuccinic anhydride sizing agent is ordinarily applied bydispersing it in a cationic or amphoteric hydrophilic substance such asa starch or a polymer. The starch or polymer-dispersed alkenylsuccinicanhydride sizing emulsions have been added to the pulp slurry before theformation of a paper web. This type of addition of alkenylsuccinicanhydride sizing emulsions to the papermaking system is commonly calledwet-end addition or internal addition of alkenylsuccinic anhydride.

Unfortunately, the addition of alkenylsuccinic anhydride to the wet endof the papermaking machine has several disadvantages. Internally addedalkenylsuccinic anhydride emulsions are never totally retained on thefiber. The portion that is not retained is free to react with water orother components of the papermaking system and can form deposits at thewet-end of the paper machine, or can then be carried to the press ordrying sections of the paper machine and form paper or board defects.Further, internal addition of alkenylsuccinic anhydride emulsions hasthe potential for interacting with other wet-end additives, such asbrightening agents, defoamers or dispersants, biocides, dyes, strengthagents, etc.

Further, increases in filler addition, such as calcium carbonate fillerat the wet-end of the paper making system have led to an increase insize demand as well. Filler particles have a relatively high surfacearea as compared to cellulose fiber and readily adsorb internally addedsizing agents. Alkenylsuccinic anhydride, which is adsorbed onto calciumcarbonate filler particles, leads to a less efficient sizing, requiringhigher doses as compared to treatment of unfilled paper webs sized withcellulose reacted alkenylsuccinic anhydride sizing agent.

Efforts to develop compositions and methods that surface treat fibroussubstrates have failed to produce a simple, effective starch-basedsystem that imparts useful sizing properties to a fibrous substrate andthat reduces or eliminates the need to use sizing agents at the wet endof a papermaking process. For example, conventional surface sizes,styrene acrylate emulsions, styrene acrylics, styrene maleic anhydrides,polyurethanes and the like require an internal size to be efficient.

U.S. Pat. No. 6,162,328 discloses a method for sizing paper that adds asizing composition containing mixtures of cellulose-reactive andcellulose non-reactive size dispersions to the surface of the paper. Thecellulose non-reactive sizes are polymeric materials such as copolymersof styrene or substituted styrenes with vinyl monomers containingcarboxyl groups. Cellulose-reactive sizes include sizes such as ketenedimers and multimers, alkenylsuccinic anhydrides, organic epoxides, acylhalides, fatty acid anhydrides from fatty acids and organic isocyanates.The starch may be of any type, including but not limited to oxidized,ethylated, cationic and pearl starch, and is preferably used in aqueoussolution. The cellulose-reactive size dispersions and non-reactive sizedispersions may be added with a solution of starch or starch derivativebefore being applied to the paper.

U.S. Pat. No. 6,162,328 requires the combination of at least onecellulose-reactive size and at least one cellulose non-reactive size.This combination allows one to add alkenylsuccinic anhydride or alkylketene dimer to the size press by balancing properties of both types.The requirement that combinations of polymeric materials be used makesthe composition more expensive and complicated as compared to singlesizing component addition. Further, it does not include any criticalityin the ratio of starch to the cellulose-reactive size.

U.S. Pat. No. 4,872,951 discloses blends of alkenylsuccinicanhydride-treated and cationic starches for use as external sizes ofpaper and paperboard products. The blends contain 30-90% (by wt.) of thealkenylsuccinic anhydride-treated starch, which is a monoester of thestarch and an alkyl- or alkenylsuccinate and 10-70% (by wt.) cationicstarch. The invention requires a reaction product of starch withalkenylsuccinic anhydride combined with cationic starch, which is addedto the surface of the paper. Manufacturing this reaction product is anadditional process step. In addition, the document's emphasis oncationic starches does not teach how non-ionic and anionic starchescould be used in emulsions to effectively deliver alkenylsuccinicanhydride to a fibrous substrate and impart useful sizing properties.

WO 02/08514 describes the preparation of a sizing emulsion that containsa sizing agent, and an inorganic particulate emulsifying agent capableof forming an emulsion and water. The sizing agent can be 2-oxetanonedimer or multimer, alkenylsuccinic anhydride, rosin or carbamoylchloride. The inorganic particulate emulsifying agent is selected fromclay, silica, zeolite, mica, calcium carbonate, phosphate or sulfate;aluminum oxide, hydroxide, phosphate or silicate; magnesium phosphate orsilicate; polyaluminum chloride, phosphate or silicate and ferrous orferric phosphate, silicate or oxide. According to the patent, theaddition of the inorganic particulate emulsifying agent allows one toadd alkenylsuccinic anhydride to the size press. Example 28, acomparative example, discloses that a conventionally preparedalkenylsuccinic anhydride “emulsion comprising surfactant and starchdoes not work in the size press . . . ”

For the foregoing reasons, there is a need to develop a method thatavoids the deposits that are often associated with internally addedalkenylsuccinic anhydride sizing agents or ketene dimer sizing agents tothe papermaking processes.

For the foregoing reasons, there is a need to develop sizingcompositions that provide for nearly 100% retention onto the surface ofthe preformed fiber web.

For the foregoing reasons, there is a need to develop a surface appliedalkenylsuccinic anhydride sizing system that is more efficient than aninternally applied alkenylsuccinic anhydride sizing system.

For the foregoing reasons, there is a need to develop sizingcompositions that impart useful sizing properties to a fibrous substratewhen the sizing compositiontreats a fibrous substrate.

SUMMARY

The invention relates to an aqueous sizing composition comprising (a) anemulsion comprising an alkenylsuccinic anhydride component containingalkenylsuccinic anhydride particles suspended in a first starchcomponent containing emulsifying starch selected from the groupconsisting of non-ionic starches, cationic starches, anionic starches,and mixtures thereof, and (b) a second starch component selected fromthe group consisting of non-ionic starches, cationic starches, anionicstarches and mixtures thereof, such that the alkenylsuccinic anhydridecomponent and the starch in the emulsion and the second starch componentare present at a starch:alkenylsuccinic anhydride component weight ratiothat is sufficiently high to enable the sizing composition to impartuseful sizing properties to a fibrous substrate when the sizingcomposition contacts the fibrous substrate.

The invention also relates to a method for making a sizing compositioncomprising the sequential steps of (a) emulsifying alkenylsuccinicanhydride with a first starch component containing starch selected fromthe group consisting of non-ionic starches, anionic starches, cationicstarches and mixtures thereof, and thereby forming an emulsion, and (b)combining the emulsion with a second starch component selected from thegroup consisting of non-ionic starches, ionic starches, and mixturesthereof, and thereby forming an aqueous sizing composition comprising(a) an emulsion comprising alkenylsuccinic anhydride componentcontaining alkenylsuccinic anhydride particles suspended in a firststarch component containing emulsifying starch selected from the groupconsisting of non-ionic starches, ionic starches, and mixtures thereof,and (b) a second starch component selected from the group consisting ofnon-ionic starches, ionic starches and mixtures thereof, such that thealkenylsuccinic anhydride component and the starch in the emulsion andthe second starch component are present at a starch:alkenylsuccinicanhydride component weight ratio that is sufficiently high to enable thesizing composition to impart useful sizing properties to a fibroussubstrate when the sizing composition contacts the fibrous substrate.

In one embodiment, the invention relates to an aqueous sizingcomposition comprising: (a) an emulsion comprising an alkyl ketene dimercomponent containing alkyl ketene dimer particles suspended in a firststarch component containing emulsifying starch selected from the groupconsisting of non-ionic starches, cationic starches, anionic starches,and mixtures thereof, and (b)a second starch component selected from thegroup consisting of non-ionic starches, cationic starches, anionicstarches and mixtures thereof, such that the alkyl ketene dimercomponent and the starch in the emulsion and the second starch componentare present at a starch: alkyl ketene dimer weight ratio that issufficiently high to enable the sizing composition to impart usefulsizing properties to a fibrous substrate when the sizing compositioncontacts the fibrous substrate.

The invention also relates to a method for sizing with the sizingcomposition of this invention.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims.

DESCRIPTION

The invention is based on the remarkable discovery that by emulsifyingalkenylsuccinic anhydride with starch, forming an emulsion, and thenadding a starch component to the emulsion under carefully controlledconditions, it is now possible to make a simple, yet highly effectivesizing composition that imparts useful sizing properties to a fibroussubstrate when the sizing composition contacts the fibrous substrate ata size press. The invention is also based on the discovery that even ifthe sizing composition made in accordance to the invention containshydrolyzed alkenylsuccinic anhydride (HASA), the sizing composition canimpart useful sizing properties to fibrous substrates so long as thestarch to alkenylsuccinic anhydride size ratio is sufficiently high.Advantageously, the use of the sizing composition reduces or eliminatesdeposition or sticking at the size press, calendar stack, or dryingsection of a paper machine.

The phrase “useful sizing properties” as used herein, means sizingproperties that are useful for a paper product's intended use.Conversely, the phrase “useless sizing properties” as used herein, meanssizing properties of that are not useful for a paper product's intendeduse. The term “emulsion” as used herein refers to emulsions made inaccordance with the invention, which when combined with an additionalstarch component, forms a sizing composition that is particularly usefulwhen applied at any location in a papermaking process after which afibrous sheet has formed, e.g., a size press or coater.

The invention relates to an aqueous sizing composition that includes (a)an emulsion containing an alkenylsuccinic anhydride component containingalkenylsuccinic anhydride particles suspended in a first starchcomponent containing emulsifying starch selected from the groupconsisting of non-ionic starches, ionic starches, and mixtures thereof,and (b) a second starch component selected from the group consisting ofnon-ionic starches, cationic starches, anionic starches and mixturesthereof. The alkenylsuccinic anhydride component and the starch in theemulsion and the second starch component are present at astarch:alkenylsuccinic anhydride component weight ratio that issufficiently high to enable the sizing composition to impart usefulsizing properties to a fibrous substrate when the sizing compositioncontacts the fibrous substrate. In one embodiment, alkyl ketene dimer isused instead of alkenyl succinic anhydride. In another embodiment,mixtures of alkenylsuccinnic anhydride and alkyl ketene dimer are used.

The sizing composition of the invention is specially designed for use atsize presses. The sizing composition of this invention reduces oreliminates the need for the use of sizing agents at the wet end of apapermaking process.

The first starch component used to make the emulsion generally includesany starch that can emulsify alkenylsuccinic anhydride and form anemulsion that can be combined with additional starch to form a sizingcomposition in accordance to the invention. Generally, the first starchcomponent includes starches that have been modified and are generallyanionic or non-ionic in nature. However, the first starch component caninclude amphoteric or cationic starches, e.g., starches that are alsoused in size presses.

Suitable starches are typically anionic or nonionic, and may includethose where the base corn, potato, wheat, tapioca or sorghum-basedstarch is modified through the use of enzymes, high temperatures, and orchemical/thermal converting techniques. Chemical modifications includebut are not limited to oxidation, acid modification, heat, acetylation,and hydroxyethylation. Examples of suitable starches include but are notlimited to Penford's Douglas® 3012 oxidized dent corn starch, Cargill'sFilmflex® 60 hydroxyethylated dent corn starch, and Staley's Ethylex®2035 hydroxyethylated dent corn starch.

The starch can be used in the form of an aqueous starch solution. Theviscosity of a starch solution can vary from about 10 cP to about 200 cPat a typical size press solution temperature. Advantageously, typicalhot starch temperatures can be used for emulsification and the sizingcomposition containing the emulsion can still impart useful sizingproperties. The starch temperature can vary from about 60 to about 200°F. (from about 15 to about 93° C.). The starch solids need also not bemodified, but can be if desired. The starch solids can range from about1 to about 20 wt. %, and preferably from about 5 to about 13 wt. %. Inone embodiment, cationic starches used for wet end emulsification can beacidified to a pH ranging from about 4.0 to about 7, or preferably fromabout 4.0 to about 5.0. The pH of the first starch component can be usedat its autogenous pH. The pH can but does not need to be adjusted. ThepH of the starch component is generally from about 5 to 9, or preferablyfrom about 7 to about 8.5.

The first starch component is used in an amount that is sufficient tomake an emulsion in accordance with the invention. Generally, the firststarch component is present in the emulsion at a starch:alkenylsuccinicanhydride component weight ratio that is at least about 0.2:1. In oneembodiment, the first starch component is generally present in theemulsion at a starch:alkenylsuccinic anhydride component weight ratiothat ranges from about 0.2:1 to about 10:1, preferably from about 0.2:1to about 7:1, or preferably from about 0.5:1 to about 2:1. In anotherembodiment, the first starch component is generally present in theemulsion at a starch:alkenylsuccinic anhydride component weight ratiothat ranges from about 0.2:1 to about 20:1.

The alkenylsuccinic anhydride component generally includesalkenylsuccinic anhydride compounds composed of mono unsaturatedhydrocarbon chains containing pendant succinic anhydride groups. Thealkenylsuccinic anhydride compounds are generally liquid and may bederived from maleic anhydride and suitable olefins. The alkenylsuccinicanhydride compounds may be solid.

Generally speaking, the alkenylsuccinic anhydride compounds may be madeby reacting an isomerized C₁₄-C₂₀ mono olefin, preferably an excess ofan internal olefin, with maleic anhydride, at a temperature and for atime sufficient to form the alkenylsuccinic anhydride compound.

If the olefin to be employed in the preparation of the alkenylsuccinicanhydride compounds is not an internal olefin as is the case forexample, with α-olefins, it may be preferable to first isomerize theolefins to provide internal olefins. The olefins that may be used in thepreparation of the alkenylsuccinic anhydride compounds may be linear orbranched. Preferably, the olefins may contain at least about 14 carbonatoms. Typical structures of alkenylsuccinic anhydride compounds aredisclosed, for example, in U.S. Pat. No. 4,040,900, incorporated hereinby reference in its entirety. Alkenylsuccinic anhydride compounds andmethods for their preparation are described, for example, in C. E.Farley and R. B. Wasser, “The Sizing of Paper, Second Edition,” editedby W. F. Reynolds, TAPPI Press, 1989, pages 51-62, the disclosures ofwhich are hereby incorporated herein by reference in its entirety.

The alkenylsuccinic anhydride component may contain some hydrolyzedalkenylsuccinic anhydride. The amount of hydrolyzed alkenylsuccinicanhydride (HASA) may range from about 1 to about 99 wt. %, based on thetotal weight of the alkenylsuccinic anhydride component.

The alkenylsuccinic anhydride component is generally present in theemulsion in an amount that is at least about 0.01 wt. %, or from about0.1 to about 20 wt. %, or from about 0.3 wt. % to about 15 wt. %, basedon the total weight of the emulsion.

The emulsion is generally made by emulsifying a suitable amount ofalkenylsuccinic anhydride with a suitable amount of starch underconditions that produce an emulsion, which when combined with the secondstarch component, forms a sizing composition that imparts useful sizingproperties to a fibrous substrate during or after the sizing compositioncontacts a fibrous substrate.

Preferably, the emulsion is made by passing the alkenylsuccinicanhydride and a suitable amount of starch solution at a suitablestarch:alkenylsuccinic anhydride component weight ratio through ashearing device that provides sufficient energy to form an emulsion. Thealkenylsuccinic anhydride should not be exposed to water beforeemulsification process and the starch should be completely cooked.Uncooked starch particles may result in poor emulsion quality due to thefact that uncooked particles may lead to coalescence as well as resultin mechanical wear to the shearing device.

The pressure and temperature at which the emulsion is made aresufficient to make an emulsion that can be combined with the secondstarch component and form a sizing composition that imparts usefulsizing properties to a fibrous substrate when the sizing compositioncontacts the fibrous substrate. In one embodiment the inlet pressure ofa suitable emulsification device, e.g., a shearing device, is about 10psig at a temperature ranging from about 120 to about 150° F. (fromabout 48 to about 66° C.), and the outlet pressure ranges from about 150to about 160 psig at a temperature ranges from about 130 to about 160°F. (from about 54 to about 71° C.). The primary starch flow to asuitable shearing device, e.g., a Burks pump, can range from about 0.8to about 2.0 gallon per minute (gpm), preferably about 1.5 gpm, and mostpreferably about 1.0 gpm.

In one embodiment, the emulsion is made from an alkenylsuccinicanhydride component that further contains a surfactant component. Thesurfactant component facilitates the emulsification of thealkenylsuccinic anhydride with the first starch component when theemulsion is made. Generally, the surfactants are anionic or nonionic orcan be cationic and can have a wide range of HLB values.

Examples of suitable surfactants include but are not limited to alkyland aryl primary, secondary and tertiary amines and their correspondingquatemary salts, sulfosuccinates, fatty acids, ethoxylated fatty acids,fatty alcohols, ethoxylated fatty alcohols, fatty esters, ethoxylatedfatty esters, ethoxylated triglycerides, sulfonated amides, sulfonatedamines, ethoxylated polymers, propoxylated polymers orethoxylated/propoxylated copolymers, polyethylene glycols, phosphateesters, phosphonated fatty acid ethoxylates, phosphonated fatty alcoholethoxylates, and alkyl and aryl sulfonates and sulfates. Examples ofpreferred suitable surfactants include but are not limited to amides;ethoxylated polymers, propoxylated polymers or ethoxylated/propoxylatedcopolymers; fatty alcohols, ethoxylated fatty alcohols, fatty esters,carboxylated alcohol or alkylphenol ethoxylates; carboxylic acids; fattyacids; diphenyl sulfonate derivatives; ethoxylated alcohols; ethoxylatedfatty alcohols; ethoxylated alkylphenols; ethoxylated amines;ethoxylated amides; ethoxylated aryl phenols; ethoxylated fatty acids;ethoxylated triglycerides; ethoxylated fatty esters; ethoxylated glycolesters; polyethylene glycols; fatty acid esters; glycerol esters; glycolesters; certain lanolin-based derivatives; monoglycerides, diglyceridesand derivatives; olefin sulfonates; phosphate esters; phosphorus organicderivatives; phosphonated fatty acid ethoxylates, phosphonated fattyalcohol ethoxylates; polyethylene glycols; polymeric polysaccharides;propoxylated and ethoxylated fatty acids; alkyl and aryl sulfates andsulfonates; ethoxylated alkylphenols; sulfosuccinamates;sulfosuccinates.

In one embodiment, the surfactant component includes an amine selectedfrom the group consisting of trialkyl amine of the formula (I):

dimethyl sulfate quaternary salt of trialkyl amine of the formula (I),benzyl chloride quaternary salt of trialkyl amine of the formula (I),and diethyl sulfate quaternary salt of trialkyl amine of the formula(I), in which R₁ is methyl or ethyl, R₂ is methyl or ethyl, and R₃ isalkyl having 14 to 24 carbon atoms. In another embodiment, thesurfactant excludes this amine. The surfactant levels can range fromabout 0.1 weight % up to about 20 weight % based on the alkenylsuccinicanhydride component.

The particles of the emulsion generally have a median particle size thatis about 0.5 microns or higher. The median particle size of the emulsioncan vary, depending on the application, the type of starch used foremulsification, and the starch properties. In one embodiment, the medianparticle size of the emulsion ranges from about 0.1 to about 50 microns,or from about 0.5 to about 30 microns. It will be appreciated that theparticles suspended by the emulsifying starch can exhibit a wide rangeof particle distributions. The ability to use an emulsion having such awide range of particle distributions is advantageous, because they areeasier to prepare. It is generally recognized that emulsions used in wetend applications require relatively narrower and smaller particle sizedistributions to provide effective sizing. Preparing emulsions havingsuch relatively narrower and small particle size distributions,(customarily prepared to apply alkenylsuccinic anhydride at the wet end)can be demanding from starch quality perspective. The particle sizedistribution of the emulsion of this invention is preferably mono-modal.However, in some cases, the distribution can be bimodal or multimodal.

The second starch component that is combined with the emulsion to formthe sizing composition can generally be any starch, which when combinedwith the emulsion, enables the formation of a sizing composition inaccordance to the invention. Generally, the starches in the secondstarch component are the same starches that are used in the first starchcomponent. In one embodiment, the first starch component and the secondstarch component are both obtained from the size press starch solution.Unlike the first starch component, the second starch component isgenerally used in an amount that is more than the amount of starch inthe first starch component. The use of the second starch component inthis invention is critical.

The sizing composition is made by combining the emulsion with the secondstarch component. The emulsion can be combined with the second starchcomponent by any suitable means, e.g., by mixing. Preferably, theemulsion and the second starch component are combined in-line. When theemulsion is made a temperature that is less than about 40° C., theemulsion is generally heated by the second starch component when theemulsion is combined with the second starch component, such that thetemperature of the resulting sizing composition ranges from more thanabout 40° F., e.g. from more than about 40 to about 200° F. (about 94°C.) or 150° F. (from about 4 C to about 66° C.), or from about 55 toabout 100° F. (from about 13° C. to about 38° C.). Alternatively, whenthe emulsion is made at a temperature that is more than above about 40°F., the temperature of the resulting aqueous sizing composition is alsogenerally more than above 40° F., e.g. from more than about 40° F., or50° F. (10° C.) to about 200° F.(about 94° C.). When the emulsion ismade at a temperature that, is more than above about 40° F., thetemperature of the emulsion is generally lower than the temperature ofthe second starch component before it is combined with the second starchcomponent. In one embodiment, when the first component is made at atemperature that is more than above about 40° F., the temperature of thefirst component is the same or greater than the temperature of thesecond starch component before it is combined with the second starchcomponent. As such, the emulsion is not added directly to a surface of afibrous substrate, but rather the emulsion is combined with the secondstarch component to form an aqueous sizing composition under conditionsthat would be expected to cause hydrolysis, and then the resultingsizing composition is added to the fibrous substrate.

The sizing composition preferably has a starch:alkenylsuccinic anhydridecomponent weight ratio that is sufficiently high to enable the sizingcomposition to minimize coalescing at papermaking operating conditionsand to impart useful sizing properties to a fibrous substrate when thesizing composition contacts the fibrous substrate. Thestarch:alkenylsuccinic anhydride component weight ratio is critical,because if the sizing composition recirculates in the system over timeand the starch:alkenylsuccinic anhydride weight ratio is notsufficiently high, the sizing composition may unduly coalesce.

Generally, the emulsion and the second starch component of the sizingcomposition have a starch:alkenylsuccinic anhydride component weightratio that is at least about 10:1. The ranges of thestarch:alkenylsuccinic anhydride component weight ratios may range fromabout 10:1 or 20:1 to about 100:1 or more. In one embodiment, thestarch:alkenylsuccinic anhydride component weight ratio ranges fromabout 10:1 to about 200:1, preferably from about 60:1 to about 120:1.

Water is the major component of the sizing composition. Generally, thewater forms at least about 95 wt. %, or at least about 90 wt. % or atleast about 80 wt. % of the sizing composition.

The sizing composition can contain other materials. For instance, in oneembodiment, the sizing composition can contain synthetic polymers thatfunction as stabilizers. Examples of suitable polymeric stabilizersinclude vinyl addition and condensation polymers having anionic,cationic, non-ionic and amphoteric charge characteristics with a chargesubstitution range varying from 0 to about 90%, and more preferably from0 to about 10%. Further, the molecular weight of aforementionedsynthetic polymeric stabilizer would fall into the range of from about10,000 to about 2.0 million daltons, or from about 200,000 to about 1million daltons. All molecular weights mentioned herein are weightaverage.

In another embodiment, the sizing composition further contains surfacesizing agents. However, this is not necessary. Suitable surface sizingagents include but are not limited to styrene maleic anhydridecopolymers, styrene acrylic acid copolymers, polyurethane dispersionsand styrene acrylate emulsions. Preferred styrene maleic anhydridecopolymers are copolymers of styrene or substituted styrene with vinylmonomers such as maleic anhydride and their partially esterified orhydrolyzed counterparts. An example is Baysize™ S 48. Preferred styreneacrylic acid copolymers are copolymers of styrene or substituted styrenewith vinyl monomers such as acrylic acid and methacrylic acid. Examplesare Baysize™ S 210 and 225. Preferred polyurethane dispersions arecopolymers of isocyanate or diisocyanates and amines or alcohols.Examples are Graphsize™ A, C, and T. Preferred styrene acrylateemulsions are copolymers of styrene, substituted styrene oracrylonitrile with acrylate or methacrylate esters. Examples areBaysize™ S AGP, BMP, and 850, Basoplast™ 400DS styrene acrylateemulsion. On a dry basis, the weight ratio of the alkenylsuccinicanhydride component to the additional sizing agent ranges from about1:0.2 to about 1:50.

In one embodiment, the sizing composition contains less than about 1 to50 wt. % of an additional sizing agent to the alkenylsuccinic anhydridecomponent. In other embodiments, the sizing composition contains morethan about 0.5:1 wt. ratio additional sizing agent to thealkenylsuccinic anhydride component, or less than about 50:1 wt. ratioadditional sizing agent to the alkenylsuccinic anhydride component.

The fibrous substrate treated with the sizing composition can be anysubstrate of a paper product, which when treated with the sizingcomposition made in accordance to the invention, acquires sizingproperties that are suitable for its intended use. In one embodiment,the fibrous substrate includes bleached and unbleached paper orpaperboard containing calcium carbonate, titanium dioxide and clayfilled paper products. The paper product made from the fibrous substratemay include paper or board, bleached or unbleached that is treated onthe surface in a size press or by spraying with a sizing composition ofthe invention.

The invention is particularly beneficial for sizing board products, finepaper products or newsprint paper products. Board is typically a papermachine produced fiber web of heavier weight than paper. Generally, theweight of board ranges from about 120 to about 400 grams per squaremeter, (gsm). Board pulps can be bleached or unbleached virgin softwood,hardwood types or be made of a blend of recycled paper composed of oneor more of the following: corrugated boxes, old newsprint, mixed officewaste, and old magazines, the latter two containing calcium carbonatefiller. Newsprint is essentially wood-containing coated and uncoatedmagazine and newspaper papers made from ground wood pulp, which is pulpnot chemically treated or a combination of ground wood, and recycledfurnishes. Fine paper generally is referred to as printing and writingpaper, excluding newsprint. Generally, the weight of fine paper rangesfrom about 40 to about 120 grams per square meter, (gsm). Specificapplications include magazines, catalogs, books, commercial printing,copying and business forms, and stationary. The pulp used in themajority of these grades is chemically treated, with limited recycle orwood-containing pulp. Printing and writing paper are generally made frombleached chemical pulps, (e.g., kraft pulping or sulfite pulping), andcontain calcium carbonate levels of from about 5 to about 30%. They mayalso partially contain deinked/recycled bleached waste paper, (sortedmixed office waste).

In use, the invention encompasses a process for sizing a paper productthat involves (a) forming a fibrous sheet from a pulp slurry, and (b)treating a surface of the fibrous sheet with the sizing composition ofthis invention. The sizing composition of the invention is added to asurface of a fibrous substrate at an amount that is sufficiently high toimpart useful sizing properties to the resulting paper product. Thesizing composition can be added to a fibrous substrate by any way thatenables the sizing composition to adsorb the sizing composition onto thesurface of the fibrous substrate. The sizing composition penetrates intothe fibrous substrate in an amount depended on surface applied starchpick-up. In one embodiment, the sizing composition can be applied tounbleached kraft or wood containing papers. The sizing composition ispreferably made on-site and used soon after it is prepared.

In one embodiment, the sizing composition is applied onto the surface ofthe formed web at an alkenylsuccinic anhydride component dosage (poundsper ton of dry paper) that is at least about 0.1, or from about 0.1 toabout 10, or from about 0.5 to about 5, or preferably from about 0.5 toabout 3.0. Particularly advantageous dosages of the alkenylsuccinicanhydride component for making board paper products range from about 1.5to about 3.0, preferably from about 1.5 to about 2.5 pounds per ton ofdry paper. Particularly advantageous dosages for making fine paperproducts range from about 0.1 to about 5 pounds per ton of dry paper, orfrom about 0.5 to about 2.0, or preferably from about 0.5 to about 1.5pounds per ton of dry paper. Particularly advantageous dosages formaking newsprint paper products range from about 0.1 to about 5, fromabout 0.1 to about 3 or from about 0.1 to about 1.5. Other suitableranges may from about about 0.1 to about 1.0, preferably from about 0.2to about 0.7 pounds per ton of dry paper.

Stated in weight percent, the amount of the alkenylsuccinic anhydridecomponent in the fibrous substrate can be at least about 0.005 wt. % andcan range from about 0.005 to about 1 wt. %, based on weight of fibroussubstrate produced, or preferably from about 0.025 to about 0.5 wt. % onthe same basis.

The temperature at which the sizing composition is used is generallyless than about 180° F. (about 82° C.), and can range from about 120° F.(about 49° C.) to about 180° F. (about 82° C.), or from about 140° F.(about 60° C.) to about 160° F. (about 71° C.). Due to the high ratio ofstarch:alkenylsuccinic anhydride component in the sizing composition,higher temperatures are possible than normally encountered in theemulsification of alkenylsuccinic anhydride in starch for internaladdition. The pH condition in which the sizing composition is used isgenerally from about 5 to about 9, or from about 7 to about 8.

A fibrous substrate treated with a sizing composition of the inventionacquires sizing properties that are appropriate for its intended use.Generally, a fine paper product made with the sizing composition willexhibit sizing properties that have at least 20 seconds of inkpenetration holdout, as described in TAPPI standard method T530 om96,preferably from about 20 to about 500 seconds, or preferably from about50 to about 200 seconds.

For board products, the sizing composition is capable of sizing a boardfibrous substrate so that the resulting paper product exhibits a Cobbsizing value (based on 2 minute test) ranging from about 50 to about 120grams per square meter, depending on end use of the board produced. Cobbsizing is a measure of the amount of liquid, generally water, which isadsorbed into the surface of a board or paper sample in a pre-statedamount of time, (in this case 2 minutes) using standardized equipmentand procedures as described in TAPPI Method T441 om98. Alternatively, aboard paper product made with the sizing composition can exhibit Cobbsizing values ranging from about 30 to about 120 gsm, or preferably fromabout 50 to about 80 gsm.

For fine paper products, the sizing composition is capable of sizing afibrous substrate so that the resulting paper product exhibits a Cobbsizing value (based on 1 minute) ranging from about 18 to about 40 gsm.Alternatively, depending on the grade of fine paper, the invention canimpart from 20 Seconds Hercules Size Test (HST, known as “TAPPI 530”, 1%formic acid, 80% reflectance) to 500 seconds of resistance topenetration.

For newsprint paper products, the sizing composition is capable ofsizing a fibrous substrate, and producing a resulting paper product thatexhibits sizing properties ranging from about 10 to about 100 seconds,as measured by a water drop test (based on 5 μL water drop size),depending on end use of publication grades being made. Water drop testis a commonly used test in newsprint applications where the time for thewater drop to penetrate into the fibrous substrate is measured.

Paper products made with the sizing composition of the invention canalso contain an internally added sizing agent so that pre-size presssizing has anywhere from about 2 to about 10 seconds of HST for goodsize press runnability.

When it is desirable to practice a process in which some sizing agent isadded to the wet end, a wet end sizing agent component is added to apulp slurry and a fibrous sheet is formed from the slurry. The fibroussheet is then treated with a sizing composition of the invention and thefibrous substrate is sized.

The wet end sizing agent component can include any sizing agent that isused in the wet end and, as such, includes those sizes believed to becapable of forming covalent chemical bonds by reaction with the hydroxylgroups of cellulose. Suitable sizes for use in the wet end sizing agentcomponent include ketene dimers and multimers, alkenylsuccinicanhydrides, organic epoxides containing from about 12 to 22 carbonatoms, acyl halides containing from about 12 to 22 carbon atoms, fattyacid anhydrides from fatty acids containing from about 12 to 22 carbonatoms and organic isocyanates containing from about 12 to 22 carbonatoms. Ketene dimers and multimers are known and described in U.S. Pat.No. 6,162,328, incorporated herein in its entirety.

In one embodiment, the wet end sizing agent component contains cationicstarch. Suitable cationic starches include those starches that aretypically used in the wet end. In another embodiment, the wet end sizingagent component contains cationic starch and alkenylsuccinic anhydride.In another embodiment, the wet end sizing component can be the emulsionused to make the sizing composition of the invention. In thisembodiment, some emulsion that would ordinarily be used to make thesizing composition of this invention is reserved for use as the wet endsizing component. When cellulose-reactive sizing agents are added to thewet end and the sizing composition of the invention is used to surfacetreat a fibrous substrate, the weight ratio of (i) the sizing agentapplied at the wet-end to (ii) the weight ratio of the alkenylsuccinicanhydride component in the sizing composition, is preferably less thanabout 1:1, or preferably less than about 0.5:1.

Applicants do not understand why, despite subjecting the sizingcomposition of this invention to conditions which cause rapid hydrolysisof alkenylsuccinic anhydride, the sizing composition imparts usefulsizing properties to fibrous substrates. Without being bound by theory,it is believed that the relatively high ratio of starch toalkenylsuccinic anhydride component in the sizing composition impartsuseful emulsifying and stabilizing properties.

The invention reduces or eliminates the amount of sizing agent used atthe wet end, and thereby reduces or eliminates wet end interaction withother chemical additives and furnish components that are known to causepaper machine cleanliness problems. In one embodiment, thealkenylsuccinic anhydride in the wet end sizing agent component is 50%or less of the total alkenylsuccinic anhydride used during an operatingperiod. In another embodiment, the alkenylsuccinic anhydride in the wetend is present in an amount that is 40% or less, or 30% or less than 20%or less than 10% of the total cellulose-reactve sizing agents usedduring an operating period.

The alkenylsuccinic anhydride component (or alkyl ketene dimercomponent) component contained in the sizing composition, when appliedto a surface of a fibrous substrate, is retained in the fibroussubstrate at higher levels as compared to when alkenylsuccinic anhydrideis added to a pulp slurry.

The invention also enables its user to produce the same amount of paperthat would ordinarily be produced by known processes by using lesssizing agent. In one embodiment, the invention uses less than 50 percentor from about 70 to about 30 percent less sizing agent that is used inan ordinary process and still produces the same amount of paper withoutthe problems ordinarily encountered with known sizing processes. Theinvention also provides a system that enables its user to use lessamounts of alkenylsuccinic anhydride without sacrificing the quality oramount of paper that is produced at a mill.

Since problems ordinarily encountered with conventional sizing processesare avoided and a higher retention of size is obtained by directlytreating a fibrous substrate, it is now possible for papermakers toproduce more paper with less sizing agent than they have been accustomedto using. The invention allows papermakers to run papermaking machinesfor prolonged period of times without problems typically encounteredwith ordinary sizing compositions, e.g., problems with runnability,deposit formation, or inconsistent quality of paper products. Theinvention, for instance, allows paper machines to be run for longperiods of time without visible deposition to the size press or calendarstack.

The invention is primarily directed to embodiments in which the sizingcomposition of the invention is made with an emulsion containing analkenylsuccinic anhydride component. The invention, however, alsoincludes embodiments in which the emulsion is made withcellulose-reactive agents other than alkenylsuccinic anhydride. Forinstance, in one embodiment, the sizing composition can be made with anemulsion containing emulsified cellulose-reactive agents selected fromthe group consisting of isocyanates and acid anhydrides, and alkylketene dimer(AKD).

As such, in one embodiment, the invention can be made or practiced withAKD instead of ASA. As used herein, the term “AKD” refers to alkyl andalkenyl ketene formed into dimers with a chemical structure accepted bythose of ordinary skill in the art where AKD contains a hydrophobicgroup containing more than about 4 carbon atoms and selected from alkyl,alkenyl, aralkyl or aralkenyl groups, as defined above. Preferably, eachhydrocarbon group is, independently, a hydrophobic group containing fromabout 4 carbon atoms to about 36 carbon atoms. AKD sizing agents aredescribed in detail in several references, for example, U.S. Pat. Nos.3,992,345 and 5,510,003; in J. W. Davis et al., TAPPI 39 (1), 21 (1956);and in R. E. Cates et al., “Alkyl Ketene Dimer Sizes”, Chapter 2 in TheSizing of Paper, 2nd Edition, W. F. Reynolds, Ed., Tappi Press, 1989,pp. 33-50. Specific examples of AKD sizing agents useful in the instantinvention include but are not limited to octyl ketene dimer, decylketene dimer, dodecyl ketene dimer, tetradecyl ketene dimer, hexadecylketene dimer, octadecyl ketene dimer, eicosyl ketene dimer, docosylketene dimer, tetracosyl ketene dimer, and those prepared by knownmethods from organic acids and naturally occurring mixtures of fattyacids such as those found in palmitoleic acid, oleic acid, rincinoleicacid, linoleic acid, linolenic acid, coconut oil, palm oil, olive oiland peanut oil. Mixtures of any of such acids may also be used.Preferred AKD sizing agents include but are not limited to thosecomprising at least one alkyl or alkenyl group comprising from about 8to about 36 carbon atoms. More preferred AKD sizing agents include butare not limited to hexadecyl, octadecyl and oleyl ketene dimer. It isunderstood that the embodiments in which AKD is used instead of ASA, thedescription of the sizing compositions containing ASA described above(and methods of making and using the compositions) can also be used forsizing compositions in which AKD is used. Accordingly, when the term“alkenylsuccinic anhydride” or “ASA” is used above to describe theinvention, the term “AKD” can be also be used instead of the term“alkenylsuccinic anhydride” or “ASA.” In one embodiment, the AKDexcludes 2 oxetanone ketene multimer.

The invention is further described in the following illustrativeExamples in which all parts and percentages are by weight unlessotherwise indicated.

EXAMPLES Example 1

Example 1 is an overview of an application of alkenylsuccinic anhydrideat the size press in a recycled board mill. No deposits or runnabilityissues due to hydrolysis of alkenylsuccinic anhydride in hot starchdispersion were encountered.

Procedure

Alkenylsuccinic anhydride was emulsified in nonionic oxidized starch (ablend of waxy maize and dent corn), using a high shear turbine pump. Thealkenylsuccinic anhydride flow rate was about 114 lb/hr. The flow rateof 1.5 gpm of the oxidized starch was used for emulsification and anadditional flow of 3 gpm of the starch was used for immediate dilutionof the emulsion. The starch solids ranged from 7-10%. No pH adjustmentor temperature cooling was done before emulsification. The pH of thestarch was about 7 and the temperature in the pump ranged from 140 to160° F. (60 to 71° C.).

The sizing composition, formed once the emulsion was added to the sizepress starch, contained about 0.12% alkenylsuccinic anhydride, at astarch:alkenylsuccinic anhydride component ratio ranging from 60:1 to90:1. The composition of the recycled furnish was a mix of mixed officewaste and old corrugated container board. During application of sizepress alkenylsuccinic anhydride, no internal size was added. Internalstarch and alum were completely eliminated as well.

Table 1 below shows the reduction in size dosage with size pressapplication of alkenylsuccinic anhydride in a board mill. Sizing ismeasure by the Cobb test. (TAPPI) test method T441. Cobb is a measure ofthe amount of water pick-up in a designated amount of time by the papersubstrate. It is obtained by subtracting the dry weight of a sample fromthe wet weight of a sample. Thus a lower Cobb value translates to highersizing. TABLE 1 Average Sizing 30-minute Cobb (g/m² top/ Avg. DoseSizing Additive Application g/m² bottom) Dose Reduction InternalEmulsified in cationic 120 ± 20 4.3 N/A alkenylsuccinic wet-end starch;Alum lb/ton anhydride added as a promoter. Surface Emulsified in non 120± 20 2.5 42% alkenylsuccinic ionic size press starch lb/ton anhydride at0.5/1 starch:size ratio; sizing composition starch:size ratio - 80:1

Example 2

Example 2 illustrates the use of the invention in a fine paperapplication. The application of the same dosage of alkenylsuccinicanhydride at the size press provided a much lower Cobb value. Theexample illustrates how a size press applied alkenylsuccinic anhydrideprovides a clear economic advantage for the papermaker by loweringchemical costs.

The example is an illustration of the application of alkenylsuccinicanhydride at the size press on a pilot plant machine. Because of therequired lower chemical dosages for this pilot plant operation, thepreparation of the alkenylsuccinic anhydride emulsion was completed in abatch form.

Procedure The alkenylsuccinic anhydride was emulsified inhydroxyethylated dent corn starch, where the starch solids were 7%. Thestarch pH was about 7, and the starch temperature of about 30-35° C. Foremulsification, a high shear industrial blender was used. Thepreparation of the emulsion was done by taking 1429 grams of starchsolution and 100 grams of alkenylsuccinic anhydride for a 1:1 starch toalkenylsuccinic anhydride component ratio providing a finalconcentration of 6.5% alkenylsuccinic anhydride in starch solution. Theemulsion was prepared by emulsifying at high shear for 30 seconds. Theemulsion was added to the size press starch. Enough sizing emulsion wasadded to obtain a pickup of 2.25 lb/ton of active size. Based on starchpick-up and dosage requirement, the final alkenylsuccinic anhydrideconcentration in the sizing composition was about 0.15% for astarch:size ratio of about 60:1.

Table 2 describes the papermaking conditions and Table 2a shows thereduction in size dosage with size press application of alkenylsuccinicanhydride, in accordance to the invention, in fine paper application.TABLE 2 Machine Type: Fourdrinier Pilot Machine MachineProduction/Speed: 60-85 lb/hr; 85 ft/min. Paper Grade: 70 g/m² writingpaper Furnish Type: Bleached Kraft w/20% PCC Filler Loading Size PressType: Flooded Nip Starch Pick-up at Size Press: 126 lb/ton

TABLE 2a 2-Minute Percent Cobb Improvement Sizing Additive Application(g/m²) Avg. Dose in sizing Internal Emulsified in cationic 114 2.25lb/ton NA alkenylsuccinic Starch at 1:1 starch to anhydrideAlkenylsuccinic anhydride component ratio; final starch:size ratio 4:1Surface Emulsified in 33 2.25 lb/ton 71% alkenylsuccinichydroxyethylated anhydride Starch at 1:1 starch to alkenylsuccinicanhydride component ratio; final solution starch:size ratio ˜60:1

Examples 3-72 Procedures, Tests, Materials

Paper Preparation Procedures

The papers used in these examples were prepared from two sources. Oneset was a pilot paper machine. The furnish was 30% bleached softwoodkraft refined to 420 Canadian Standard Freeness and 70% bleachedhardwood kraft refined to 350 Canadian Standard Freeness. Four paperswere prepared using an anionic, polyacrylamide retention aid. Paper Awas a 70 g/m² sheet containing 14.9% calcium carbonate (ALBACART™ 5970,Specialty Minerals Inc.,) and no internal sizing. Paper B was a 70 g/m²sheet containing 14.9% calcium carbonate and a pre-determined amount ofadded internal size, ASA, (BAYSIZE® I 18 synthetic size). Paper C was a125 g/m² sheet containing 25% calcium carbonate (ALBACAR 5970) with nointernal sizing. Paper D was a 125 g/m² sheet containing 25% calciumcarbonate (ALBACAR 5970) and a pre-determined amount of added internalsize (BAYSIZE I 18 synthetic size). Water emulsions prepared for use ininternal addition were made with cationic starch (Penford Hi-Cat CWSstarch), ASA internal size at a weight ratio of 1:1 (starch:size) usinga Ross Homogenizer The second set of papers was prepared on a commercialpaper machine from mixed office waste. The basis weight of this paperwas 126 g/m² and contains 7 weight percent calcium carbonate (ALBACAR5970) and no internal size. This paper was designated as Paper E.

Starch Solutions

A starch solution was prepared by making a 15% starch solids slurry of acommercially available surface size starch (Filmflex® 60 starch,Cargill) in deionized water that has been adjusted to pH 7.0±0.2 witheither 0.5N HCl or 0.5N NaOH, (hereby referred to as Treated Water A)and heating the mixture to 95° C. for 1 hour. This was called StarchSolution A.

To 150 parts of Starch Solution A were added 600 parts of Treated WaterA. Then, 0.5N NaOH solution was added drop-wise to provide a starchsolution of pH 7.1-7.3. This is a 3% starch solution called StarchSolution B.

To 150 parts of Starch Solution A were added 171.4 parts of TreatedWater A. Then, 0.5N NaOH solution was added drop-wise to provide astarch solution of pH 7.1-7.3. This is a 7% starch solution calledStarch Solution C.

Surface Application Procedure A

The appropriate sizing composition was then used to treat paper samples.The desired dosage was calculated based upon the liquid pick-up of thecomposition on the dry paper sheet. This was determined by measuring theweight difference between the dry sheet and the sheet that has beendipped into the surface treatment solution (and pressed). The variousPapers A, B, C, D, or E were cut to a suitable size, weighed, dippedinto the various sizing compositions, pressed at a pressure of 12 psig,and then dried at 240° F. for 35 seconds. The dose levels were reportedin lb/ton, i.e., pounds of dry sizing agent per ton of dry paper.

Treatment Effectiveness Tests

The treatment effectiveness of the sizing agents and conditions wasdetermined by performing some of the various test described below. Thegeneral procedures for these tests were provided below.

Test A Ink Penetration Holdout

Ink Penetration Holdout was measured using a method similar to thatdescribed in TAPPI Method T 530 pm-89 except that an instrument was usedas described in U.S. Pat. No. 5,483,078. The test measures the time (inseconds) for the reflectance of the paper on the side opposite thatcontacting the ink to decreases to 80% of the initial value. The inkconsists of 1.25% Naphthol Green B dye buffered to pH 7. The test valueswere normalized for basis weight of the paper assuming that the valuesvary as the cube of the basis weight. Results were expressed in units ofseconds.

Image Analysis

Image analysis was performed using an Optomax Sorcerer image analysissystem equipped with morphometry application software, a stereo zoommicroscope with CCD camera and ring fiber optic illumination. Severaltypes of tests were used.

Test B Black Image Analysis

A commercially available ink jet printer was used to print onto a testsheet several rows of the letter “H” which was a bold, 8 point, Arialfont. The areas of the four letters were then measured and averaged toprovide the “black letter area”. A smaller letter area corresponds toless spreading or wicking of the inked area. Results were expressed inunits of mm².

Test C Color Bleed

Color bleed was determined by measuring the areas of black lettersprinted on a yellow background, in a similar fashion as described in theBlack Image Analysis; a color inkjet printer must be used. Images offour letters were averaged to provide the “letter area”. A smallerletter area corresponds to less spreading or wicking of the inked area.Results were expressed in units of mm².

Test D Optical Density

Solid, black areas of at least 1-cm² were printed onto the sheet to betested. The optical density (OD) of the printed areas was measured witha commercially available X-Rite Spectrodensitometer. Values were theaverage of five measurements. The values were dimensionless. A higheroptical density value was generally indicative of improved printability.

Test E Particle Size

Commercially available, light-scattering, particle analyzers, HoribaLA-300 and Horiba LA-700, were used to determine the particle size ofthe emulsions. Results were reported as the median particle size in μm.

Examples 3 through 7 show the effect of various starch to ASA weightratios.

Example 3

To a household blender was added 120 parts of Starch Solution A. Addedto this solution was 1.25 parts of Treated Water A. The speed on theblender was set to low. Alkenylsuccinic anhydride (ASA; BAYSIZE® S 180synthetic size), 2.25 parts, was added into the vortex in one portion.After the addition, the speed was changed to high and held for 3minutes.

Example 4

The procedure of Example 3 was repeated except that 121.4 parts ofStarch Solution A and 3.6 parts of ASA were used.

Example 5

The procedure of Example 3 was repeated except that 41.7 parts of StarchSolution A, 6.3 parts of ASA, and 77 parts of Treated Water A were used.

Example 6

The procedure of Example 3 was repeated except that 20.9 parts of StarchSolution A, 6.3 parts of ASA and 97.8 parts of Treated Water A wereused.

Example 7

The procedure of Example 3 was repeated except that 8.3 parts of StarchSolution A, 6.3 parts of ASA and 110.4 parts of Treated Water A wereused.

Example 8

Sizing emulsions prepared in Examples 3 through 7 were used to treatPaper A. Each of the emulsions were added to additional Starch SolutionA, the second starch component to make a total sizing composition forpaper treatment. Surface Application Procedure A was used to test theseexamples on Paper C. The effectiveness of sizing was determined byprinting the treated sheets on a commercial printer (HP Deskjet 648C)and measuring performance with the tests for Black Image Area and ColorBleed at 2 and 3 lb/ton, conducted as described in the test proceduresabove. The results were provided below in Table 3. TABLE 3 Size BlackImage Color Emulsion Starch:Size Dose Particle Size Area Bleed ExampleRatio (lb/ton) (μm) (mm²) (mm²) starch   1:0 — — 2.352 2.31 3   5:1 20.48 1.927 1.93 4   8:1 2 0.48 1.908 1.975 5   1:1 2 0.56 1.927 1.934 60.5:1 2 0.66 1.925 1.985 6 0.5:1 3 0.66 1.913 1.941 7 0.2:1 2 0.63 1.9141.958 7 0.2:1 3 0.63 1.899 1.954 base sheet — — — 2.446 2.326

These examples show that over a wide range of starch to ASA weightratios, effective sizing properties were achieved as measured byprinting properties.

Example 9 illustrates the effectiveness of this invention when largeparticle size is employed.

Example 9

A sizing system of the instant invention was used to provide surfacetreatment size to a commercial machine that produces linerboard, asdescribed in Examples 1 and 2, except that the furnish was predominantlymixed office waste. The emulsion was prepared by passing the size pressstarch solution (7% solids; ethylated corn starch) through a commercialemulsifier into which ASA (BAYSIZE® S 180) size was fed. The emulsionwas directly added to the size press (flooded-nip) feed line. A sampleof the emulsion was withdrawn to determine that the median particle sizewas 8.28 μm according to test E. Thirty-minute Cobb values of 142 g wereachieved, well within acceptable specification range of 120-150 g/m².

This example shows that particle sizes above 1 micron demonstrateeffective sizing properties.

Examples 10-16 show the influence of hydrolyzed ASA on sizingperformance as evidenced by printing properties.

Example 10

To a household blender was added 41.7 parts of Starch Solution A and 77parts of Treated Water A. The speed on the blender was set to low. Inone portion, 6.3 parts of alkenylsuccinic anhydride, (ASA, BAYSIZE® S180 Synthetic Size) was added into the vortex. After the addition, thespeed was changed to high and held for 3 minutes.

Sample A

Hydrolyzed ASA was prepared by taking equimolar amount of ASA and waterand stirring the mixture over several days at 50° C. Infrared analysisindicated complete hydrolysis with no anhydride peaks present. Thismaterial was labeled as Sample A.

Example 11

To a household blender was added 41.7 parts of Starch Solution A, 77part of Treated Water A. The speed on the blender was set to low. In oneportion, 5.6 parts of alkenylsuccinic anhydride and 0.6 parts of SampleA was added to this solution. The speed of the blender was changed tohigh and maintained at that stirring rate for three minutes.

Example 12

The procedure of Example 11 was repeated except that the 4.7 parts ofASA and 1.6 parts of Sample A was used.

Example 13

The procedure of Example 11 was repeated except that the 3.1 parts ofASA and 3.1 parts of Sample A was used.

Example 14

The procedure of Example 11 was repeated except that the 0.9 parts ofASA and 5.4 parts of Sample A was used.

Example 15

The procedure of Example 11 was repeated except that the 0.6 parts ofASA and 5.6 parts of Sample A was used.

Example 16

Sizing emulsions prepared in Examples 10 through 15 were used to sizepaper by the Surface Application Procedure A. Each of the emulsions wereseparately added to additional Starch Solution A, the second starchcomponent, to make a total sizing composition for paper treatment.Surface Application Procedure A was used to treat the Paper C. Theeffectiveness of sizing was determined by printing the treated sheets ona commercial printer (HP Deskjet 648C) and measuring performance withthe tests for Black Image Area and Color Bleed at 2 to 23 lb/ton,conducted as described in the test procedures above. The results wereprovided below in Table 4. TABLE 4 Black ASA Image Emulsion ASA:HASADose Particle Size Area Color Bleed Example Ratio (lb/ton) (μm) (mm²)(mm²) Control base sheet — — 2.446 2.326 Control Starch only — — 2.3522.310 10 ASA only 2 0.83 1.951 2.036 10 ASA only 2.25 0.83 1.961 2.03611 9:1 2 0.57 1.964 2.020 11 9:1 2.25 0.57 1.959 2.028 11 9:1 2.5 0.571.968 2.072 12 3:1 2.25 0.4 2.000 2.057 12 3:1 2.7 0.4 1.946 2.045 123:1 3 0.4 1.991 2.042 13 1:1 4 0.54 1.960 2.064 13 1:1 4.5 0.54 1.9582.040 14 1:6 14 1.33 2.045 2.052 14 1:6 15.75 1.33 2.008 2.059 15 1:9 201.4 2.035 2.084 15 1:9 23 1.4 2.054 2.080

These examples show that over a wide range of alkenylsuccinicanhydride/hydrolyzed alkenylsuccinic anhydride (ASA/HASA) ratio, a smallparticle size and effective printing properties were achieved.

Examples 17-20

These Examples show that over a wide range of ASA/HASA ratios, a smallparticle size and effective printing properties are achieved.

In these examples, in situ-generated hydrolyzed ASA was used. Theemulsion was prepared according to Example 3 except that 106.7 parts ofStarch Solution A, 277.3 parts of Treated Water A, and 16 parts of ASAwere used to give a 4% ASA solution with a 1:1 starch:size ratio. Theemulsion was placed in a vessel equipped with an overhead stirrer. Thevessel was heated in a water bath maintained at 50° C. This was ReactionA. Periodically, aliquots of Reaction A were withdrawn and analyzed foranhydride content and surface sizing efficiency. The amount of anhydridein the initial emulsion was measure using a morpholine titration (ref.:R. B. Wasser, “The Reactivity of Alkenylsuccinic Anhydride: It'sPertinence to Alkaline Sizing,” 1985 Alkaline Papermaking Conference,page 17, TAPPI Press). Surface sizing experiments were conductedaccording to Surface Treatment Procedure A. The solids content of theReaction A aliquot was added to Starch Solution B such that the dose ofthe size on the treated sheet was 0.5 pounds of size per ton of drypaper. Paper B was treated for the examples.

Every 1.5 hours for 4.5 hours, an aliquot of the initial emulsion thatwas stirring at 50° C. was removed and tested for % anhydride andparticle size. Sheets were treated as described with the aging emulsion.The resulting sheets were tested for sizing using Test A. Twelve sizingmeasurements were made on each sheet and averaged. The results are shownin Table 5. TABLE 5 Elapsed % Hydrolyzed Particle Example Time ASA ASA,as % of Size Ink No. (hours) Dose Total (μm) Penetration base sheet 0 54base sheet + 0 74 starch 17 0   0.5 5.1 0.667 492 18 1.5 0.5 19.5 0.726536 19 3.0 0.5 70.3 0.773 364 20 4.5 0.5 94.9 0.803 222

These examples illustrate that an effective amount of ink penetrationhold-out was exhibited in paper treated with sizing emulsion containinghydrolyzed ASA. Surprisingly, there was no separation or deposition ofthe ASA or hydrolyzed ASA in the starch/ASA emulsion. This solutionremained stable for several days.

Examples 21-30

The following examples demonstrate the utility of the instant inventionusing two different surfactants over a range of surfactant levels in thesizing agent. Surfactant A was AEROSOL® OTS surfactant (CytecIndustries, Inc.). Surfactant B was Rhodafac®RS610 surfactant (Rhodia).

Example 21

In a blender was charged 142 parts of Starch Solution C. The blender wasturned on a low speed and into the vortex was added in 9.99 parts of ASAand 0.01 part of Surfactant A. The blender was placed on the high speedsetting and run for one minute.

Example 22

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.9 parts of ASA and 0.1 part of Surfactant A were used.

Example 23

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.5 parts of ASA and 0.5 part of Surfactant A were used.

Example 24

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.0 parts of ASA and 1.0 part of Surfactant A were used.

Example 25

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.99 parts of ASA and 0.01 part of Surfactant B were used.

Example 26

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.9 parts of ASA and 0.1 part of Surfactant B were used.

Example 27

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.5 parts of ASA and 0.5 part of Surfactant B were used.

Example 28

An emulsion was prepared in a similar manner as in Example 21, exceptthat 9.0 parts of ASA and 1.0 part of Surfactant B were used.

Example 29

Sizing emulsion prepared in Examples 21-28 were used to size paper bythe Surface Application A. Each of the emulsions were separately addedto additional Starch Solution B, the second starch component, to make atotal sizing composition for paper treatment. Surface Application A wasused to treat Paper A. The effectiveness of the sizing was determined byTest A Ink Penetration Holdout described above. Emulsion particle sizefor each of the emulsions was measured using the Test E Particle Sizedescribed above. The results were provided below in Table 6. TABLE 6Surfactant Ink Emulsion Level ASA Dose Penetration Example Surfactant(%) (lb/ton) (sec) Control Unsized basesheet 0 0 0 plus starch 21AEROSOL ® OTS 0.1 3 740 25 Rhodofac ® RS610 0.1 3 593 22 AEROSOL ® OTS 13 693 26 Rhodofac ® RS610 1 3 573 23 AEROSOL ® OTS 5 3 434 27 Rhodofac ®RS610 5 3 388 24 AEROSOL ® OTS 10 3 365 28 Rhodofac ® RS610 10 3 447

Example 30

Sizing emulsion prepared in Examples 21-28 were used to size paper bythe Surface application A. Each of the emulsions were separately addedto additional Starch Solution B, the second starch component, to make atotal sizing composition for paper treatment. Surface Application A wasused to treat Paper B. The effectiveness of the sizing was determined byTest A Ink Penetration Holdout described above. Emulsion particle sizefor each of the emulsions was measured using the Test E Particle sizedescribed above. The results were provided below in Table 7. TABLE 7Surfactant ASA Ink Emulsion Level Dose Penetration Example Surfactant(%) (lb/ton) (sec) Control Sized basesheet plus 0 0 3 starch 21AEROSOL ® OTS 0.1 1 637 25 Rhodofac ® RS610 0.1 1 685 22 AEROSOL ® OTS 11 793 26 Rhodofac ® RS610 1 1 637 23 AEROSOL ® OTS 5 1 698 27 Rhodofac ®RS610 5 1 588 24 AEROSOL ® OTS 10 1 745 28 Rhodofac ® RS610 10 1 744

The data of these examples illustrate the fact that even though thesizing solution contains a varying amount of surfactant, an effectiveamount of ink penetration holdout was observed in the sheet.

Examples 31-39

These Examples illustrate the effect of starch dilution on emulsionstability for a variety of starches.

Starch Preparation Procedure A

In a jacketed reactor heated by steam 141 parts of as-is dry starch and859 parts of Treated Water A were slurried. The vessel was heated withsteam until the liquid achieved a temperature between 95° C.-100° C. andwas then held at that temperature for 1 hour. The starch solid was equalto 12-wt percent. The solution pH was adjusted to 7.2±0.1 with 0.5NNaOH, and used as illustrated in the examples below.

Example 31

A solution of anionic, oxidized dent corn starch (Clearsol® 10 Gum;Penford Products Co.) was prepared according to the Starch PreparationProcedure A. This starch solution was used for the preparation of theASA emulsion and for the dilution of the ASA emulsion as it is describedbelow.

In a household blender 60.0 parts of the starch solution and 52.8 partsof Treated Water A were added. The blender was turned on low speed, andinto the vortex was introduced 7.2 parts of ASA (BAYSIZE® S 180synthetic size). Upon completion of addition, the speed was changed tohigh for three minutes. The weight ratio of starch to ASA in thisemulsion is 1:1. This was ASA Emulsion A.

A total of 16.67 parts of ASA Emulsion A was diluted with 158.41 partsof the starch solution and 24.92 parts of Treated Water A to provide afinal concentration of 0.5 wt % ASA. The final weight ratio of starch toASA was 20:1.

Comparative Example 32

The procedure of Example 31 was repeated, except that 16.67 parts ofEmulsion A was diluted with 183.33 parts of Treated Water A to provide afinal concentration of 0.5 wt % ASA. The weight ratio of starch to ASAwas 1:1.

Example 33

A solution of oxidized, dent corn starch was prepared according to theStarch Preparation Procedure A. This starch-solution was used for thepreparation of the ASA emulsion and for the dilution of the ASA emulsionas it is described below.

In a household blender 60.0 parts of the starch solution and 52.8 partsof Treated Water A were added. The blender was turned on low speed, andinto the vortex was introduced 7.2 parts of ASA (BAYSIZE S 180 syntheticsize). Upon completion of addition, the speed was changed to high forthree minutes. The weight ratio of starch to ASA in this emulsion is1:1. This was ASA Emulsion B.

A total of 4.0 parts of ASA Emulsion B was diluted with 48.06 parts ofthe starch solution and 147.94 parts of Treated Water A to provide afinal concentration of 0.12 wt % ASA. The final weight ratio of starchto ASA was 25:1.

Comparative Example 34

The procedure of Example 33 was repeated, except that 4 parts ofEmulsion B was diluted with 196.0 parts of Treated Water A to yield anASA concentration of 0.12 weight percent with a starch to ASA ratio of1:1.

Example 35

A solution of cationic, acid-thinned waxy maize starch (Charge®+34;Cargill, Inc.) was prepared according to the Starch PreparationProcedure A. This starch solution was used for the preparation of theASA emulsion and for the dilution of the ASA emulsion as it is describedbelow.

In a household blender 60.0 parts of the starch solution and 52.8 partsof Treated Water A were added. The blender was turned on low speed, andinto the vortex was introduced 7.2 parts of ASA (BAYSIZE S 180 syntheticsize). Upon completion of addition, the speed was changed to high forthree minutes. The weight ratio of starch to ASA in this emulsion is1:1. This was ASA Emulsion C.

A total of 16.67 parts of Emulsion C was diluted with 158.41 parts ofthe starch solution and. 24.92 parts of treated Water A. Theconcentration of ASA in this example was 0.5 weight percent and theratio of starch to ASA was 20:1.

Comparative Example 36

The procedure of Example 35 was repeated, except that 16.67 parts ofEmulsion C were diluted with 183.33 parts of Treated Water A.

The concentration of ASA in this example was 0.5 weight percent and theratio of starch to ASA was 1:1.

Example 37

The procedure of Example 35 was repeated, except that 4 parts ofEmulsion C were diluted with 48.06 parts the starch solution and 147.94parts of Treated Water A. The concentration of ASA in this example was0.12 weight percent and the starch to ASA ratio was 25:1.

Comparative Example 38

The procedure of Example 35 was repeated, except that 4 parts ofEmulsion C were diluted with 196.0 parts of Treated Water A. Theconcentration of ASA in this example was 0.12 weight percent and thestarch to ASA ratio was 1:1.

Example 39

The diluted ASA emulsions from Example 31, 32, 33, 34, 35, 36, 37, and38 were separately placed in a 70° C. water bath and mixed with anoverhead stirrer for one hour. After 1 hr, the mixing was stopped, andthe diluted emulsions were stored at room temperature for 7 days. Theobservations regarding emulsions quality were made. These observationsindicated that at the high starch to ASA ratio of 25/1 and 20/1, the ASAemulsions were well dispersed in the solution. At the low starch to ASAratio of 1/1, the ASA emulsions separated from the solution, creating awhite layer on the top or bottom of the container. The results werepresented in Table 8. TABLE 8 ASA Starch: Concen- ASA trationObservation Example Type of Starch Ratio (%) After 7 days 31 Anionic20:1  0.5 No emulsion Dent Corn Starch separation Clearsol 10 GumComparative Anionic 1:1 0.5 Emulsion was 32 Dent Corn Starch separatedClearsol 10 Gum 33 Anionic 25:1  0.12 No emulsion Dent Corn Starchseparation Comparative Anionic 1:1 0.12 Emulsion was 34 Dent Corn Starchseparated 35 Cationic 20:1  0.5 No emulsion Waxy Maize Starch separationCharge + 34 Comparative Cationic 1:1 0.5 Emulsion was 36 Waxy MaizeStarch separated Charge + 34 37 Cationic 25:1  0.12 No emulsion WaxyMaize Starch separation Charge + 34 Comparative Cationic 1:1 0.12Emulsion was 38 Waxy Maize Starch separated Charge + 34

These examples show that the higher starch to size ratios promoteemulsion stability with a number of different starches.

Examples 40-44

These Examples show the positive impact of higher starch ratios onapplication performance

Surface Application Procedure B

A Werner Mathis laboratory size press was adapted for use inflooded-nip, paper size press applications. The laboratory flooded-nipsize press consists of two, hard rubber rollers. The nip pressurebetween these two rollers was adjustable. The speed of rollers wasvaried to maximize pick-up. Pick-up of the size press solutions wasdetermined by weighing test sheets before and after passing through thenip contain the targeted size press liquid. The test liquids were thendosed with the appropriate amount of treatment solution (real solidsbased upon dry starch pick-up). Test solutions were added to the nip andthe paper sample was fed through the nip. The dose was expressed aspounds of real substrate per ton of dry paper. The treated paper samplewas immediately passed through a rotary drum dryer heated at 240° F. for35 sec. The samples were then conditioned at 50% relative humidity and70° C. for 24 hours before testing.

Example 40

A starch solution was prepared according to Starch Preparation ProcedureA included in the set of SAMPLES 31 to 39, except that an ethylated,dent corn starch (Filmflex® 60 starch, Cargill) was used. The starchconcentration of this solution was 12 weight percent. This starchsolution was used to make the ASA emulsion and to prepare the size presssolution.

In a household blender 40.06 parts of the starch solution and 75.14parts of Treated Water A were added. The blender was turned on lowspeed, and into the vortex was introduced 4.8 parts of ASA (BAYSIZE S180 synthetic size). Upon completion of addition, the speed was changedto high for three minutes. The concentration of ASA in this emulsion was4.0 weight percent and the weight ratio of starch to ASA was 1:1. Thiswas ASA Emulsion A.

A size press solution was prepared by adding 4.33 parts of Emulsion A to37.53 parts of the starch solution and 112.47 parts of Treated Water A.The weight ratio of starch to ASA in the size press solution was 27:1.The size press solution was used to surface treat three sheets of PaperA (70 g/m² sheets containing 14.9% calcium carbonate and no internalsizing) according to the Surface Application Procedure B. In thismanner, a dose of 2 dry pounds of size was added per ton of dry paperfiber.

Example 41

The procedure of Example 40 was repeated, except that the size presssolution was prepared by adding 4.53 parts of Emulsion A to 25.02 partsof the starch solution and 124.98 parts of Treated Water A. The weightratio of starch to ASA in the size press solution of this example was18:1.

Example 42 (Comparative)

The procedure of Example 40 was repeated, except that the size presssolution was prepared by adding 4.65 parts of Emulsion A to 12.51 partsof the starch solution and 137.49 parts of Treated water A. The weightratio of starch to ASA in the size press solution of this example was9:1.

Example 43 (Comparative)

The procedure of Example 40 was repeated, except that the size presssolution was prepared by adding 4.78 parts of Emulsion A to 6.25 partsof the starch solution and 143.75 parts of Treated Water A. The weightratio of starch to ASA in the size press solution of this example was5:1.

Example 44 (Comparative)

The procedure of Example 40 was repeated, except that the size presssolution was prepared by adding 4.84 parts of Emulsion A to 150 parts ofTreated Water A. The weight ratio of starch to ASA in the size presssolution of this example was 1:1.

Summary of Examples 40-44

The effectiveness of Sizing Emulsions described in Examples 40, 41, 42,43 and 44 was determined by black letter area and letter area colorbleed tests performed on paper sized with these sizing compositions.These tests are described above. The results in Table 9 show that thesizing compositions of the invention, Example 40 (27/1 starch/ASA ratio)and example 41 (18/1 starch/ASA ratio), provided improved black letterarea and color bleed letter area than comparative sizing compositionsfrom examples 42, 43, and 44. These comparative examples have astarch/ASA ratio of 9/1, 5/1 and 1/1, respectively. TABLE 9 Black ImageStarch/ASA Area Color Bleed Example # Ratio (mm²) (mm²) 40 27/1  2.0512.267 41 18/1  2.060 2.321 42 comparative 9/1 2.151 2.444 43 comparative5/1 2.218 2.450 44 comparative 1/1 2.225 2.469

Examples 45-48

These examples show that there was a trend of increased black image areaand color bleed with a decrease in the starch:ASA ratio, indicatingpoorer sizing efficiency.

Example 45

A starch solution was prepared according to Starch Preparation ProcedureA included in the set of SAMPLES 31 to 39, except that an ethylated,dent corn starch (Filmflex® 60 starch, Cargill) was used. The starchconcentration of this solution was 12 weight percent. This starchsolution was used to make the ASA emulsion and to prepare the size presssolution.

In a household blender 40.06 parts of the starch solution and 75.14parts of Treated Water A were added. The blender was turned on lowspeed, and into the vortex was introduced 4.8 parts of ASA (BAYSIZE S180 synthetic size). Upon completion of addition, the speed was changedto high for three minutes. The concentration of ASA in this emulsion was4.0 weight percent and the weight ratio of starch to ASA was 1:1. Thiswas ASA Emulsion A.

A size press solution was prepared by adding 4.38 parts of Emulsion A to75.0 of the starch solution and 75.0 parts of Treated Water A. Theweight ratio of starch to ASA in the size press solution was 52.4:1. Thesize press solution was used to surface treat three sheets of Paper E(126 g/m² sheets containing 7 wt % calcium carbonate and no internalsize) according to the Surface Application Procedure B. In this manner,a dose of 1.75 dry pounds of size was added per ton of dry paper fiber.

Example 46

The procedure of Example 45 was repeated, except that the size presssolution was prepared by adding 3.63 parts of Emulsion A to 37.53 partsof the starch solution and 112.47 parts of Treated Water A. The weightratio of starch to ASA in the size press solution of this Example was32:1.

Example 47

The procedure of Example 45 was repeated, except that the size presssolution was prepared by adding 3.79 parts of Emulsion A to 12.51 partsof the starch solution and 137.49 parts of Treated Water A. The weightratio of starch to ASA in the size press solution of this example was10.9:1.

Example 48 (Comparative)

The procedure of Example 45 was repeated, except that the size presssolution was prepared by adding 3.88 parts of Emulsion A to 6.25 partsof the starch solution and 143.75 parts of Treated Water A. The weightratio of starch to ASA in the size press solution of this example was5.8:1.

Summary of Examples 45-48

The effectiveness of sizing compositions described in Examples 45, 46,47, and 48 was determined by analysis using the Black Optical DensityTest. The results in Table 10 show that the sizing compositions of theinvention, Example 45 (52.4/1 starch/ASA ratio), Example 46 (32/1starch/ASA ratio) and Example 47 (10.9/1 starch/ASA ratio), providebetter black optical density than the comparative sizing compositionfrom Example 48 (5.8/1 starch/ASA ratio). TABLE 10 Example # Starch:ASARatio Optical Density 45 52.4:1 1.460 46 32.0:1 1.440 47 10.9:1 1.426 48 5.8:1 1.408

These examples show that there was a clear trend of decreasing backoptical density with the decrease of the starch/ASA ratio, indicative ofpoorer sizing.

Although the present invention has been described in detail withreference to certain preferred versions thereof, other variations arepossible. Therefore, the spirit and scope of the appended claims shouldnot be limited to the description of the versions contained therein.

1. An aqueous sizing composition comprising: (a) an emulsion comprisingan alkenylsuccinic anhydride component containing alkenylsuccinicanhydride particles suspended in a first starch component containingemulsifying starch selected from the group consisting of non-ionicstarches, anionic starches, cationic starches and mixtures thereof, and(b) a second starch component selected from the group consisting ofnon-ionic starches, cationic starches, anionic starches and mixturesthereof, wherein the alkenylsuccinic anhydride component and the starchin the emulsion and the second starch component are present at astarch:alkenylsuccinic anhydride weight ratio that is sufficiently highto enable the sizing composition to impart useful sizing properties to afibrous substrate when the sizing composition contacts the fibroussubstrate.
 2. The sizing composition of claim 1, wherein thestarch:alkenylsuccinic anhydride weight ratio is at least about 10:1. 3.The sizing composition of claim 1, wherein the emulsifying starch in thefirst starch component in the emulsion has a starch: alkenylsuccinicanhydride weight ratio ranging from about at least 0.2:1 to about 10:1.4. The sizing composition of claim 1, wherein the particles have amedian particle size ranging from about 0.5 to about 20 microns.
 5. Thesizing composition of claim 1, wherein the emulsion further comprises asurfactant component in an amount ranging from about 0.1 wt. % to about20 wt. %, based on the total amount of alkenylsuccinic anhydride.
 6. Thesizing composition of claim 1, wherein the an alkenylsuccinic anhydridecomponent includes hydrolyzed alkenylsuccinic anhydride in an amountranging from about 1 to about 99%, based on the total weight of theemulsion.
 7. The sizing composition of claim 1, wherein the sizingcomposition has a starch:alkenylsuccinic anhydride component weightratio that is sufficiently high so that when the sizing compositiontreats a fibrous substrate, the treated fibrous substrate has a Cobbsizing of less than about 150 gsm for 30 minutes or about 100 gsm fortwo minutes.
 8. The sizing composition of claim 1, wherein thestarch:alkenylsuccinic anhydride component weight ratio is sufficientlyhigh so that if the sizing composition treats a fibrous substrate, thetreated fibrous substrate retards ink penetration, giving an HST valueof at least ten seconds.
 9. The sizing composition of claim 1, whereinthe starch:alkenylsuccinic anhydride ratio is sufficiently high tominimize the sizing composition from coalescing at a temperature rangingfrom about 100 to about 180° F.
 10. The sizing composition of claim 1,wherein the suspended alkenyl succinic anhydride particles have amonomodal particle distribution.
 11. The sizing composition of claim 1,wherein the alkenyl succinic anhydride component comprising particlessuspended in non-ionic and/or ionic starch have a bimodal or amultimodal particle distribution.
 12. A fibrous substrate treated withthe sizing composition of claim
 1. 13. The fibrous substrate of claim12, wherein the substrate is paperboard.
 14. The fibrous substrate ofclaim 12, wherein the substrate is fine paper.
 15. The fibrous substrateclaim 12, wherein the substrate is a newsprint or other wood-containingpapergrades.
 16. A process for making a sizing composition comprisingthe sequential steps of: (a) emulsifying alkenylsuccinic anhydride witha first starch component containing starch selected from the groupconsisting of non-ionic starches, ionic starches, and mixtures thereof,and thereby forming an emulsion, and (b) combining the emulsion with asecond starch component selected from the group consisting of non-ionicstarches, ionic starches, and mixtures thereof, and thereby forming asizing composition comprising (1) an emulsion comprising analkenylsuccinic anhydride component containing alkenylsuccinic anhydrideparticles suspended in a first starch component containing emulsifyingstarch selected from the group consisting of non-ionic starches, ionicstarches, and mixtures thereof, and (2) a second starch componentselected from the group consisting of non-ionic starches, ionic starchesand mixtures thereof, such that the alkenylsuccinic anhydride and thestarch in the emulsion and the second starch component are present at astarch:alkenylsuccinic anhydride weight ratio that is sufficiently highto enable the sizing composition to impart useful sizing properties to afibrous substrate when the sizing composition contacts the-fibroussubstrate.
 17. A process for sizing a paper product comprising: (a)adding, to a pulp slurry, a wet end sizing agent component; (b) forminga fibrous sheet from the slurry, and (c) treating the fibrous sheet witha sizing composition comprising: (1) an emulsion comprising analkenylsuccinic anhydride component containing alkenylsuccinic anhydrideparticles suspended in a first starch component containing emulsifyingstarch selected from the group consisting of non-ionic starches, ionicstarches, and mixtures thereof, and (2) a second starch componentselected from the group consisting of non-ionic starches, ionic starchesand mixtures thereof, and thereby imparting useful sizing properties tothe fibrous substrate.
 18. The process of claim 17, wherein the wet endsizing agent component contains a sizing agent selected from the groupconsisting of ketene dimers, ketene multimers, rosin, alkenylsuccinicanhydrides, organic epoxides containing from about 12 to 22 carbonatoms, acyl halides containing from about 12 to 22 carbon atoms, fattyacid anhydrides from fatty acids containing from about 12 to 22 carbonatoms and organic isocyanates containing from about 12 to 22 carbonatoms, and combinations thereof.
 19. The process of claim 17, whereinthe wet end sizing agent component contains cationic starch and a sizingagent selected from the group consisting of ketene dimers and multimers,alkenylsuccinic anhydrides, organic epoxides containing from about 12 to22 carbon atoms, acyl halides containing from about 12 to 22 carbonatoms, fatty acid anhydrides from fatty acids containing from about 12to 22 carbon atoms and organic isocyanates containing from about 12 to22 carbon atoms.
 20. The process of claim 17, wherein the wet end sizingagent component contains cationic starch and alkenylsuccinic anhydride.21. The process of claim 17, wherein the alkenylsuccinic anhydride inthe wet end sizing agent component is present in an amount that is lessthan the total sizing agent used.
 22. The process of claim 17, whereinthe wet end sizing agent component is present in an amount that is 50%or less of the total sizing agent used.
 23. A process for sizing finepaper comprising treating a fibrous sheet with an aqueous sizingcomposition comprising: (a) an emulsion comprising an alkenylsuccinicanhydride component containing alkenylsuccinic anhydride particlessuspended in a first starch component containing emulsifying starchselected from the group consisting of non-ionic starches, ionicstarches, and mixtures thereof, and (b) a second starch componentselected from the group consisting of non-ionic starches, ionic starchesand mixtures thereof, and thereby imparting useful sizing properties tothe fine paper.
 24. The process of claim 23, wherein the sizingcomposition is added to a water box.
 25. The process of claim 23,wherein about 100% of the alkenylsuccinic anhydride in the sizingcomposition is retained in the fibrous substrate.
 26. A process forsizing a fibrous substrate comprising: (a) emulsifying alkenylsuccinicanhydride with a first starch component containing starch selected fromthe group consisting of non-ionic starches, ionic starches, and mixturesthereof, and thereby forming an emulsion, (b) combining the emulsionwith a second starch component selected from the group consisting ofnon-ionic starches, ionic starches, and mixtures thereof, and therebyforming a sizing composition comprising: (1) an emulsion comprising analkenylsuccinic anhydride component containing alkenylsuccinic anhydrideparticles suspended in a first starch component containing emulsifyingstarch selected from the group consisting of non-ionic starches, ionicstarches, and mixtures thereof, (2) a second starch component selectedfrom the group consisting of non-ionic starches, ionic starches andmixtures thereof, wherein the alkenylsuccinic anhydride and the starchin the emulsion and the second starch component are present at astarch:alkenylsuccinic anhydride weight ratio that is sufficiently highto enable the sizing composition to impart useful sizing properties to afibrous substrate when the sizing composition contacts the fibroussubstrate, and (c) treating a fibrous sheet with the sizing composition,and thereby imparting useful sizing properties to the fibrous substrate.27. The process of claim 26, wherein the substrate is paperboard. 28.The process of claim 26, wherein the substrate is fine paper.29. Theprocess of claim 26, wherein the substrate is newsprint or otherwood-containing paper grades.
 30. An aqueous sizing composition made bya process comprising: (a) emulsifying alkenylsuccinic anhydride with afirst starch component containing starch selected from the groupconsisting of non-ionic starches, ionic starches, and mixtures thereof,and thereby forming an emulsion, and (b) combining the emulsion with asecond starch component selected from the group consisting of non-ionicstarches, ionic starches, and mixtures thereof, and thereby forming thesizing composition, wherein the composition comprises: (1) firstcomponent including an emulsion comprising an alkenylsuccinic anhydridecomponent containing alkenylsuccinic anhydride particles suspended in afirst starch component containing emulsifying starch selected from thegroup consisting of non-ionic starches, ionic starches, and mixturesthereof, and (2) a second starch component selected from the groupconsisting of non-ionic starches, ionic starches and mixtures whereinthe alkenylsuccinic anhydride and the starch in the emulsion and thesecond starch component are present at a starch:alkenylsuccinicanhydride weight ratio that is sufficiently high to enable the sizingcomposition to impart useful sizing properties to a fibrous substratewhen the sizing composition contacts the fibrous substrate.
 31. A sizedfibrous substrate made by a process comprising: (a) emulsifyingalkenylsuccinic anhydride with a first starch component containingstarch selected from the group consisting of non-ionic starches, ionicstarches, and mixtures thereof, and thereby forming an emulsion, and (b)combining the emulsion with a second starch component selected from thegroup consisting of non-ionic starches, ionic starches, and mixturesthereof, and forming an aqueous sizing composition comprising: (1) anemulsion comprising an alkenylsuccinic anhydride component containingalkenylsuccinic anhydride particles suspended in a first starchcomponent containing emulsifying starch selected from the groupconsisting of non-ionic starches, ionic starches, and mixtures thereof,and (2) a second starch component selected from the group consisting ofnon-ionic starches, ionic starches and mixtures thereof; wherein thealkenylsuccinic anhydride and the starch in the emulsion and the secondstarch component are present at a starch:alkenylsuccinic anhydrideweight ratio that is sufficiently high to enable the sizing compositionto impart useful sizing properties to a fibrous substrate when thesizing composition contacts the fibrous substrate, and (c) treating afibrous substrate with the aqueous sizing composition, and therebyforming a sized fibrous substrate.
 32. The fibrous substrate of claim31, wherein the fibrous substrate is selected from the group consistingof board, fine paper, newsprint, and other wood-containing grades. 33.An aqueous sizing composition comprising: (a) an emulsion comprising analkyl ketene dimer component containing alkyl ketene dimer particlessuspended in a first starch component containing emulsifying starchselected from the group consisting of non-ionic starches, anionicstarches, and mixtures thereof, and (b) a second starch componentselected from the group consisting of non-ionic starches, cationicstarches, anionic starches and mixtures thereof, wherein the alkylketene dimer component and the starch in the emulsion and the secondstarch component are present at a starch: alkyl ketene dimer weightratio that is sufficiently high to enable the sizing composition toimpart useful sizing properties to a fibrous substrate when the sizingcomposition contacts the fibrous substrate.